A typical disc drive includes a rigid housing that encloses a variety of disc drive components. The components include one or more rotating discs having data surfaces that are coated with a medium for storage of digital information in a plurality of circular, concentric data tracks. The discs are mounted on a spindle motor that causes the discs to spin. Sliders carry transducers, which write information to and read information from the data surfaces of the discs. The slider and transducers are often together referred to as the “head.”
A slider includes a slider body having a leading edge, a trailing edge and an air bearing surface (ABS) which faces the disc surface. As the disc rotates, the disc drags air under the slider along the air bearing surface, which creates a hydrodynamic lifting force that causes the slider to lift and fly above the disc surface. The transducer is typically mounted at or near the trailing edge of the slider.
Typically, the transducer includes an inductive recording and/or write element for generating a magnetic field that aligns the magnetic moments of the data surfaces to represent desired bits of data. The write element includes a magnetic core to record magnetic transitions to the magnetized medium surface of a disc. The core is magnetically coupled to a conductive coil. Electrical current flows through the conductive coil during a write operation and generates magnetic flux in the core to record transitions in the magnetic surface coating of the rotating disc or other medium. The magnetic core includes a pair of poles, wherein each pole has a corresponding pole tip adjacent a surface opposing the storage medium. The pole tips tend to protrude when write current is flowing through the conductive coil and, thus, decreases the head-to-medium spacing. Typically, the transducer also includes a read element that is adapted to read magnetic flux transitions recorded to data tracks on the medium, which represent the bits of data.
As the areal density of media increases, the passive head-to-medium spacing is decreasing. At some point, this ever-increasing areal density of the media will cause the head to undesirably come into contact with the medium.
More recently, a writer heater has been placed in the write element of the transducer to generate active control of pole tip protrusion regardless of whether the write current is passing through the conductive coil. As a result, the pole tips protrude and push the write element closer to the surface of the medium, which when thermally stabilized, results in a more efficient write process. However, the protrusion generated by the writer heater causes the slider to push back from the medium and results in a smaller net head-to-medium spacing than desired. In addition, the writer heater transfers a significant amount of heat to the reader element. As the reader element temperature increases, the reader element becomes less reliable.
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.